TubeNet

Thanks for taking my call. Why do CC and F tubas have more than 4 valves? I will hang up and listen to your answer.

CC - also to play the c# above the pedal C. The real reason though is to help keep the valve oil companies in business.
Phil

Pitch is not linear. Pitch is proportional. Going up, each octave is twice the frequency of the next, so with twelve semitones to the octave each next semitone is 2^(1/12) times the pitch of the former in an equally tempered scale, which works out decimally to a factor of approximately 1.0594631.

However, brass instruments are made with fixed linear amounts of tubing. So in order for the lower pitches to not be sharp, there has to be increasingly longer tubes for each pitch going down. This is the first reason for all those valves.

Look closely and you will notice that the 1st valve loop is not simply twice as long as the second valve circuit, but a little bit more than twice as long; and the third valve slide is not three times as long as the second, but about 3 1/2 times as long, and so forth.

Yes, like trumpet players, we could use 3-valve instruments and pull slides, but even if we were adept at getting them pulled and pushed at the right time, that limits the low range to about a half octave below the lowest open conventional note on any particular tuba, especially since not all tubas have good "privileged" tones.

So the second reason for all those valves is to get the semitones between the lowest conventional pitches reachable with only three valves down to the true pedal tones.

Example with a CC 5-valve tuba. If the tuba is nominally about 196 inches long, then a whole step down from open CC to open BBb would need to add 2^(2/12) [two semitones, hence the exponential fraction of 2/12] amount of tubing, or approximately 24 inches of tubing, so the total length of the open horn plus the first valve circuit is about 220 inches. However, if you're playing low GG with the 4th valve, that is 5 semitones down, so nominally the open horn plus 4th valve needed for low GG to be in tune is 2^(5/12) of the basic length, or about 261.63 inches total. And then to get low F below that takes another 2^(2/12) amount of this longer length, or another 32.04 inches, not just another 24 inches as is needed to get from open CC to BBb. So, I have several options: play the "false" pedal tone F if the horn will play it; Play it 1+4 and pull the dickens out of 1 or 4 or both; play it 1+2+4, but that is too much to add the 2nd valve, so I either have to shove #1 if it is made short to shove on the 5th partial midline D, or lip up; or do what is now conventional: add a "long whole step" 5th valve for this purpose, since low FF is a commonly played note on a CC tuba.

So not only is this proportional-verses-linear dilemma the reason for more valves on a tuba, but it is also the whole reason for having the Blaikley/Boosey fully automatic compensating system, so that these necessary extra lengths of proportional tubing for the valve combinations for the lower semitones are added in "automatically" by re-routing the tubing back a second time through the valve block. Werden has a great explanation of this:
http://www.dwerden.com/eu-articles-comp.cfm" target="_blank" target="_blank

These are all the vagaries of the "square peg in a round hole" of trying to fit a proportional fluid Western musical system into a fixed linear instrument. And I haven't even approached the issues of temperament, overtone variances, nodal/anti-nodal tendencies, and other issues.

Thanks for the lesson in the physics of tuba music iiipopes. I can now say that I am reasonably informed as to how and why valves work on a tuba. I think I will stick to BB flat or EE flat. I am a practitioner of the KISS system of tuba playing.

Another possibility could be the popularity of CC and F tubas. Since these are arguably the most popular types of tubas in the States, companies are more likely to focus on producing more "professional grade" models in these keys. Since professionals are the most likely to utilize multiple valves, a trend has been unwittingly created where it is much easier to find a CC or F tuba with an above average number of valves as opposed to tubas in other keys. So theoretically, a CC or F tuba could have just as few valves as any other tubas, it's just that they're more popular, and thus have a higher demand for the extra valves to combat the problems everyone else has listed here.

TubaCoopa wrote:Another possibility could be the popularity of CC and F tubas. Since these are arguably the most popular types of tubas in the States . . .

I'd wager that the most "popular" tubas (i.e. the most produced and played in this country) are in BBb.

I think he ment most played by professionals, and serious students. But most highschool students and below play BBb, though they tend to be of a lesser quality and have more intonation problems.

tubainty wrote:I think he ment most played by professionals, and serious students. But most highschool students and below play BBb, though they tend to be of a lesser quality and have more intonation problems.

I'm going to save this one....

bloke wrote:F tubas (had they only 4 valves) would run out of pitches w-a-y above "low E", as that last somewhat-usable pitch (with only 4 valves) is B natural.

Did you mean A, bloke? Every Yammie F I've ever played on has a very solid low A fingered 2-3-4 (the last note of the Hungarian March from Damnation of Faust comes to mind). Bb has always worked for me as 1-2-4 and push, but so does low F on the C tuba. Might just be me, though.

Every extra valve doubles the number of possible permutations. Many fingerings will be irrelevant for Western scales, but of course the chance for a precise tuning increases with a tighter grid of pitches.

The compensating instruments hardly ever have more than four valves. They have fewer fingering permutations, but the idea is, that those fingerings available are in tune for all but two notes.

Whether you have 6 valves non-compensating or 4 valves compensating, the addition of one or more slide triggers will be helpful. bloke has a trigger on the 5th slide on his 6 valve F tuba. Many players, including myself, have a main tuning slide trigger on their compensating euphoniums.

Klaus

Rev Rob wrote:Thanks for the lesson in the physics of tuba music iiipopes. I can now say that I am reasonably informed as to how and why valves work on a tuba. I think I will stick to BB flat or EE flat. I am a practitioner of the KISS system of tuba playing.

There are 5 valve BBb and Eb tubas out there, as well. A "simple" three valve BBb will not play a B natural below the staff in tune, unless you do a lot of lipping, pull slides, or have a compensating horn - 123 is an extremely sharp combination. Many of the older horns made the 3rd slide a little too long to help with this, but then 23 is consistently flat.
The "problem" low F on a CC tuba is a comparable low Eb on a BBb tuba, this note is much less often seen. The same thing applies - can't play it (unless using an open false tone) on a 3 valver, and on a 4 valve tuba it is either 14 pull a lot, or 124 push some. I have a 4 valve Eb tuba and have to pull slides on it, and hope to someday add a 5th valve.
Nothing is ever simple.

b.williams wrote:Why do CC and F tubas have more than 4 valves?

There are many 5 valve Eb and 5 valve BBb tubas out there.
Check out http://www.wwbw.com/Tubas-Brass-Instruments1.wwbw" target="_blank" target="_blank"

More valves = more combinations of valves = one of the combinations being close to "in-tune"

And more valves make the low end more accessible. The two semitones above the first partial on any tuba
(as in these notes):
G1 or Gb1 on an F
F1 or E1 on an Eb
D1 or Db1 on an CC
C1 or B0 on an BBb
Are much easier to play with five or six valves.
Without them, lots of pulling/lipping and false tones (which are sometimes weak) need to occur.

Think of a bass trombone. The F trigger is the equivelent of the 4th valve on any tuba. The second valve on the bass bone makes Low B(semitone above first partial) possible, just like a fifth valve.

The answer is simple: better intonation and low range!

Mcordon1 wrote:

b.williams wrote:Why do CC and F tubas have more than 4 valves?

There are many 5 valve Eb and 5 valve BBb tubas out there.
Check out http://www.wwbw.com/Tubas-Brass-Instruments1.wwbw" target="_blank" target="_blank" target="_blank"

More valves = more combinations of valves = one of the combinations being close to "in-tune"

I also use my 5th valve in situations where tuning it easier with that particular slide pull. Especially on my F tuba where the 5th valve slide is practically in my face.